The Project which is subject to the EIAO comprises two termini, one at Tung Chung the other at Ngong Ping. Five towers will be located in the Country Park with two towers (2A and 2B) located on the Airport Island and one tower at Tung Chung. Two angle stations will also be provided to allow a change in direction. A maximum of 8 towers (extra tower 2B on the Airport Island) may thus be needed although this will be finalised during detailed design. The angle stations are essentially structures with turning wheels which need to be protected from the elements and to minimise wheel chatter. These angle stations will therefore be roofed structures which will be designed to blend into the surroundings as far as practicable. For the purpose of this EIA an assumption has been made that the structure will be similar to that proposed in the MTRC’s technical proposal to Government.
Concurrent projects which need to be taken into account in the EIA include the Package 1 works for Ngong Ping Sewage Treatment Works and Package 2 Ngong Ping Main Trunk Sewer and Effluent Export Pipeline. The foregoing has been subject to an EIA, with a Study Brief issued by EPD (ESB-074/2001) in May 2001, and this timing scheduled to match with the opening of the cable car in late 2005.
Consequential Development
The consequential developments arising from the Project consist of only the:
· Emergency rescue trails;
· Helicopter pad;
· Restitution of stream course at Ngong Ping; and
· Theme village
Their environmental impacts have been addressed in the following sections of this report.
From the outset of the Cable Car Project the overarching requirements have included:
· minimisation of the number of sensitive receivers affected by visual impacts;
· recognition of the unspoilt and natural beauty of the majority of the route;
· minimisation of the overall environmental impacts during both construction and operational phases through, for example, incorporating existing access trails to minimise the need to clear new tracks for emergency access and for maintenance reasons;
· selection of a route which would be of benefit to, and would be acceptable to the Po Lin Monastery;
· provision of added value to businesses in Tung Chung; and
· minimisation of impacts on the immediate environs and the provision of associated facilities (including the Ngong Ping Sewage Treatment Works).
The Study Brief, issued under ESB-068/2001 calls for, amongst other things (under Section 3.3.1.2) the EIA report to “compare the environmental impacts of different options, cable car systems, tower design, termini location and alignment and provide reasons for selecting the proposed system and alignment, and the part environmental factors played in the selection”.
Environmental factors have played a key and critical role in the selection of the route, location of termini and cable car system and other related facilities descriptions of which are important to put the Project into context. This section of the report provides an overview of the issues considered and particularly those ecological, environmental and landscape aspects which were an integral part of the selection of components of the Project. Other aspects which help to put the whole Project into perspective (such as the engineering and topographical constraints) have also been included to provide a more complete picture.
The following sections describe:
· the selection of the termini locations;
· the Alignment selected and the reasons for choosing the preferred Alignment;
· Tower locations and Angle Stations;
· Emergency Rescue and the associated Trail and helicopter touch down points;
· construction methods; and
· cable car systems.
The alignment of the cable car system is partially determined by the termini locations. As shown in Figure 2.1, various options have been considered for the alignments and the termini at Tung Chung and Ngong Ping. Alignment 1 was rejected in the preliminary assessment because of its impacts on the adjacent developments and land use implications. Six other options were thereafter considered for the alignment and six for the terminal location at Tung Chung as shown on Figure 2.2.
Location B at Tung Chung West Area (TC74)
The proposed location for the cable car terminal at Tung Chung Area 74 (TC74) is next to the Tung Chung Hau Wong Temple and was proposed because at the time there were two potentially available lots at the end of the existing footbridge to the west of the youth centre. The lots are irregular in shape with areas of 0.89ha and 0.44ha. The larger lot is a government lot covering a number of Government Land Licences and the smaller lot is a private land – Lot 125 in DD1 Tung Chung.
Location C at Pak Sha Tsui (TC 71)[1]
The proposed location for the cable car terminal in Tung Chung Area TC71 (refer to Figure 2.2) is on what was originally planned to be the future Pak Sha Tsui Island. The Pak Sha Tsui Island was planned as part of the Comprehensive Feasibility Study for Remaining Development in Tung Chung and Tai Ho (on behalf of Territory Development Department (TDD)). However this component of the development is not scheduled to be implemented in the near future and is now a long term potential development option (primarily due to the concerns expressed over environmental and ecological issues). Nonetheless the discussion relating to Pak Sha Tsui Island has been included in this Report as this component featured in the development of the options for the alignment of the cable car. The site was initially identified as providing a short and direct route (4km) to Ngong Ping. It was also considered that it would ensure a highly visible and prestigious setting for the terminal in Tung Chung Wan and would provide a scenic flight with a panoramic view of the new airport and North Lantau New Town. Location C was also favoured on account of the proximity to the future Tung Chung West MTR Station and the scope for integrated development with other tourism related uses. However, the decision was made by TDD not to reclaim Pak Sha Tsui Island in the near future, and thus the advantage of using the reclamation (especially if formed by others) no longer. Reclamation to provide a footing for the tower in isolation would be difficult to justify from an environmental, ecological (due to the proximity of the SSSI at San Tau) and cost perspective.
Location D at Pak Sha Tsui (TC72)1
The proposed location for the cable car terminal in Tung Chung Area TC72 (refer to Figure 2.2) would provide a direct route (4.2km) to Ngong Ping. The site has ample area (4.4ha) for integrating the terminal, a hotel, recreational and public transport facilities. It would be approximately 800m (on plan) and 920m along public roads from the future Tung Chung West Station. This location would allow a less visually intrusive alignment for the waterfront developments in Tung Chung West should a link to the town centre become necessary.
Location E at Tung Chung Town Centre (TC2)
The proposed location for the cable car terminal in Tung Chung Area TC2 (refer to Figure 2.2) is very close to the existing Tung Chung Station. This proposal focuses on the easy pedestrian walkway at an elevated level connecting the MTR Station and Cable Car Terminal. The elevated walkway provides a convenient public pedestrian network linking the existing town centre to the new developments on the northern waterfront of Tung Chung.
Location E1 at Tung Chung Town Centre (TC2)
This location is within Tung Chung Area TC2 and is adjacent to Location E. This location was considered to be most preferred an account of the provision of an Angle Station. The Angle Station was initially conceived as providing an additional station on the Airport Island to allow access/egress to/from the cable car system at this point. During the course of the current Study MTRC confirmed that there are no plans to convert the angle station to another an intermediate station for embarkation/disembarkation. This location is very similar to Location E apart from the requirement for rezoning for the commercial development around the Terminal within the current Government, Institution or Community (‘G/IC’) site. The angle station is located on the Airport Island, which eliminates the need for reclamation at Pak Sha Tsui, or for a footing for a tower in the “Sea Channel” which is clearly preferred from an environmental and ecological viewpoint.
Various aspects have been considered in connection with these locations, and to provide background these are summarised below.
· Accessibility to Public Transport Interchange
Location B
This location is 450m from the future Tung Chung West Station which is unlikely to be in place before 2011 as (advised by the MTRC). The site could be connected to Road P2 by extending the road half a kilometer. The location is approximately 2km from Tung Chung Station. Shuttle bus service between the cable car terminal and the existing public transport interchange at Tung Chung Central will be required. This makes the option less attractive in terms of environmental protection as vehicle emissions, noise and potential congestion may arise, and moreover it introduces the need for another form of transport to be included in the journey. This also reduces the commercial viability of this option, as it will have an adverse effect on the cable car ridership.
Location C
This location is within walking distance (570m along the MTR reserve, 720m along public roads) of the future Tung Chung West Station (albeit not likely to be in place before 2011). The location is approximately 2km from Tung Chung Station and a shuttle bus service between the cable car terminal and the existing public transport interchange at Tung Chung Central would be required. As discussed under Location B above, this makes the option less attractive in terms of environmental protection
Location D
This location is approximately 1km from the future Tung Chung West Station and over 2km from the existing Tung Chung Station. Shuttle bus service between the cable car terminal and the existing public transport interchange at Tung Chung Central will be required. As discussed under Location B, this makes the option less attractive in terms of environmental protection.
Locations E and E1
These locations are only 250m from the existing Tung Chung Station. The key difference between Locations E and E1 from the other proposed terminal locations is the ease of accessibility to the existing transport interchange in Tung Chung Town Centre. A large proportion of the cable car riders are expected to be local residents who would prefer to take the MTR to Tung Chung and change the cable car to Ngong Ping. Although there may also be direct bus routes connecting to the other proposed terminal locations at B, C and D from Kowloon and Hong Kong Island, a direct link from the MTR Station to the cable car terminal is clearly an advantage of these locations.
· Adequacy of land for a comprehensive development
Location B
One Government lot of 0.89ha and one private lot of 0.44ha owned by the Secretary for Home Affairs Incorporated have been identified at Location B. However, these lots are irregular in shape and are not particularly suitable for comprehensive development as the two lots with some adjacent private land only amount to around 2ha which is too small for a cable car terminal, tourist retail, commercial and transport development. District Lands Office/Islands (DLO/IS) verbally advised that the football field within one of the identified lots has been vested in the name of Home Affairs Department but still remains officially as private lot no. 125 in DD1TC as with the playground, latrine and the adjacent garden. The site is adjacent to Hau Wong Temple, which offers the potential for an integrated development for tourism.
Location C
The site would provide about 4.4ha of land for the terminal, hotel and associated facilities and is of regular dimensions ensuring ease of site planning. It was the original intention that this site would be developed with the cable car terminal being integrated into a hotel and retail complex and other entertainment facilities as a tourist attraction. However the plan to form Pak Sha Tsui Island has been shelved and the attractiveness of the location consequently diminished.
Location D
The availability of land in this location is similar to Location C as a large area was originally planned to be reclaimed in the future. However as the reclamation plans have been shelved and are not part of the immediate Tung Chung development plan, the “land” is no longer readily available.
Location E
The proposed location E is within the area zoned for town centre facilities including a “G/IC” (Government, Institution or Community) zone, a “DO” (District Open Space) zone, and a “C” (Commercial) zone in addition to the “CDA” (Comprehensive Development Area) zone under construction at the Tung Chung Station.
The Terminal would be located mainly in the “G/IC” zone (Planning Area 2) and next to a “C” zone which spans Tat Tung Road. Part of the “G/IC” zone would be needed as an easement for the cable car route. The part of the “C” zone nearer to the MTR station is fully required for a public transport interchange at ground level. A mix of retail and office uses has been planned for the “C” zone with a plot ratio of 3. The allowable Gross Floor Area (GFA) has been specified in the land sale document prepared by Lands Department with the mix between retail and office apparently being left to the developer to decide.
The planning intention within the Outline Zoning Plan (OZP) for Tung Chung Town Centre is to develop Tung Chung into a balanced community in support of the Hong Kong International Airport. The Tung Chung Town Centre plan includes a civic centre with a swimming pool complex in the “G/IC” zone (Planning Area 2) to serve the local community. Other than private and public residential developments, major land uses in the town centre will be commercial /office developments in the “C” zone and “CDA” zone (Planning Area 3 and 14) and a District Open Space in Planning Area 1.
In order to minimise the cable car terminal’s impacts on current planning intentions for the Tung Chung Town Centre and the “G/IC” zone, the cable car terminal, the public transport interchange, and the adjacent District Open Space could be planned and developed under an integrated design. It would allow the town centre to be developed with a coherent planning concept which will provide the greatest benefits to the amenity of the town centre.
Location E1
This site is similar to Location E where an integrated design within the "C", "G/IC" and "O" sites would be possible.
· Timely provision of the cable car link
Location B
The formation of the site would require diversion and training of the existing water stream as well as gazettal under the Foreshore and Seabed (Reclamation) Ordinance. Time is also required to resolve the Government Land Allocation and other private land’s resumption and clearance for the site area and the extension of Road P2. The statutory procedures for complying with the Ordinances make this site less attractive in programme terms.
Location C
The Pak Sha Tsui Island was planned to be an artificial island to be formed under Phase 3 of North Lantau development. If Location C was chosen as the terminal location, at least the southern corner of the Island would need to be formed in advance for the construction of the terminal and other accesses. However as noted previously the plan for the Pak Sha Tsui Island has been shelved in the intervening period between the Feasibility Study and the current EIA and has been Location C would require dedicated reclamation for the facilities with consequential impacts in terms of time among other factors.
Location D
This location is very similar to Location C but a larger area (requiring longer time for construction) of the Pak Sha Tsui Island, or part thereof, would need to be formed in advance for a timely provision of the cable car facilities. This is unlikely to be an acceptable option.
Location E
In many Outline Zoning Plans (OZPs) prepared since 1993, standard schedules to the OZP have been used, and they include the land use of “cable car route and terminal building.” In this way, the cable car use appears in two zone types in Tung Chung, namely: In all G/IC zones, “cable car route and terminal building” is in Column 1 which means it is permitted without requiring the permission of the Town Planning Board. In all “O” zones, “cable car route and terminal building” is in Column 2, which means it may be permitted with conditions on application to the Town Planning Board. There is a “C” (Commercial) zone in the town centre, but “cable car route and terminal building” appears in neither Column 1 nor Column 2. The proposed location for the cable car terminal in the Town Centre is within the “G/IC” zone with other associated facilities in the “C” zone. The cable car terminal construction could therefore start immediately due to the availability of existing land.
Location E1
Similar to Location E, Location E is within the current "G/IC" site. The cable car terminal construction could therefore start immediately after the rezoning exercise.
· Visual Impact
Location B
In order to keep the alignment further away from the existing village site at Tung Chung Area TC60, the cable car terminal has to be located to the north west corner of Tung Chung Area TC74. Such a location would be very close to the schools at TC37 and would be likely to create visual/environmental impact on the schools.
Location C
The site is within Tung Chung Area TC711 and would affect the residential development in the area. The site is also close to Tung Chung TC46 and would affect the housing site in TC46.
Location D
The site would be further away from the planned housing site at Tung Chung TC46 resulting in a lesser degree of visual/environmental impacts to the housing site.
Locations E and E1
It is considered that with the terminal located in the heart of Tung Chung Town Centre, the terminal building has great potential to become a focal point within the New Town. The movement and activities associated with the cable cars is more likely to provide a dynamic element to the Town Centre of interest rather than intrusion to the population in general.
· Ecological and Landscape Impact
Location B
This location would be on the edge of the existing land in an urban setting with small scale of loss of vegetation.
Locations C and D
These locations would require the reclamation of the Pak Sha Tsui Island (or at least part thereof) and would have potentially negative impacts on the San Tau Beach SSSI and marine water quality within the Sea Channel (depending on details of the shape)
Locations E and E1
These locations are on existing reclaimed land in an urban setting with no loss of vegetation. These are therefore highly favoured from an ecological perspective.
· Commercial Viability
Locations B, C and D
As accessibility is always a crucial factor determining the popularity and sustainability of a tourist attraction, those locations with poor accessibility would reduce the development potential and commercial viability of the Cable Car Project.
Locations E and E1
These locations provide very good connections to the public transport interchange including the Tung Chung Station as well as the bus terminus in North Lantau New Town. This would be likely to induce more people to make the journey to Tung Chung and take the cable car to Ngong Ping.
Location Y to the East of Po Lin Monastery
Terminal location Y at Ngong Ping is on the eastern corner outside the courtyard of Po Lin Monastery (refer to Figure 2.3). This site is on an existing slope and requires site formation works for constructing the terminal and other associated buildings. Moreover, the available areas of the site are constrained by the existing Youth Hostel and a number of graves which will limit the development potential of the terminal. For this location, construction of vehicular and pedestrian access is required to connect to the existing Ngong Ping Road. This would require substantial clearance of vegetation along the access route and would cause adverse ecological impact to the area.
Location X to the West of Po Lin Monastery
An alternative terminal location at Ngong Ping is located on the western side of Po Lin Monastery and is very close to the Giant Buddha (400m). The proposed location possesses the advantages of being close to the existing Ngong Ping Road and having large existing paved areas (i.e. less site clearance works are required). The terminal proposal includes redevelopment of the existing bus terminus and ‘hawker’ areas in front of Po Lin Monastery. The new cable car terminal, relocated bus terminus and the redesigned taxi/coach areas will form a new public transport interchange at Ngong Ping. This proposal for the Ngong Ping terminal received full support from the Master of Po Lin Monastery when it was mooted in the first instance but this tacit approval has been since withdrawn. It is understood however that there are no objections to the proposals from the Buddhist Community.
· Accessibility to Public Transport Interchange (PTI)
Location Y
This location is 400m from the existing PTI in front of Po Lin Monastery.
Location X
The new PTI would be able to be integrated with the Terminal development proposal.
· Adequacy of land for a comprehensive development
Location Y
This location is limited by the topography and existing structures/graves which would need to be relocated.
Location X
This location is set in around 2.8 hectares most of which are existing paved areas and to be redeveloped as open space and walking areas.
· Timely delivery of site (without considering land ownership issues)
Location Y
Large scale site formation works would be required prior to being able to use this site for terminal.
Location X
Most of the land required is existing paved area and ready for construction.
· Impacts on ecology
Location Y
Substantial clearance of vegetation is required for the construction of the terminal and emergency/ maintenance access.
Location X
Relatively small as there are large paved areas available and is close to the existing Ngong Ping Road.
· Utilities supplies/ upgrading
Location Y
In relative terms more substantial upgrading works would need to be carried out compared to Location X as this location is not close to the existing Ngong Ping Road.
Location X
It would be relatively simple to develop this location for the Ngong Ping Terminal as it is close to the existing Ngong Ping Road and connections to utilities would be relatively straight forward.
· Effects to the Ngong Ping Community
Location Y
The potential effects on the community would be less for Location X as the site is not so close to the majority of the Ngong Ping community.
Location X
This location is closer to the Ngong Ping community than Location Y, however the impact of the Terminal to the community is not expected to be large as the Terminal will still be situated some distance from the main community centre.
The proposed cable car stations/adjoining development at Tung Chung and Ngong Ping provide a unique design opportunity presented by the two significantly different locations, each having their own identity in terms of settings, building mass, layout and stylistic identities. This is important where considering the overall identity of the cable car system and its integration and harmony with its environs.
Tung Chung Terminal
Located in the heart of the Tung Chung Town Centre between Citygate and the proposed Civic Centre/ Swimming Pool Complex/ District Open Space, the cable car terminal will strategically connect Tung Chung Station and Citygate.
Ngong Ping Terminal
The Ngong Ping Terminal, in contrast to the Tung Chung Terminal is surrounded by the picturesque landscape next to the Po Lin Monastery. The design of the development must be carefully considered in order to avoid overwhelming the key buildings in the monastery especially the Main Temple. This tenet will prevail in the development of the master cultural/landscape plan. The existing bus terminus/ taxi stands will be relocated to a new Public Transport terminal cum car/ coach park in the western part of Ngong Ping to achieve a vehicle free public piazza in front of the Monastery complex to minimise the pedestrian movement and vehicular circulation conflict.A new road proposed around the development will shielded (by for example planting, fencing or similar in keeping with the character of the area and will be subject to detail design) from the pedestrian areas both for aesthetic and safety reasons.
Environmental issues have been a key factor in the selection of the components of the Project (alignment, termini locations etc) and in particular landscape and visual impacts and cultural issues have played a prominent role. It was considered that the prediction of the significance of the impacts on the Country Park and its future extensions, landscape character and visual amenity would be particularly significant when selecting the optimum alignment especially in such an attractive part of North Lantau.
Several alignments were studied and their benefits and disadvantages have been examined in detail in terms of engineering feasibility, climatic and other environmental conditions (wind shear etc.), practicality of construction and operational requirements, costs, landscape, visual and environmental impact.
While the alignment and the location of the towers need to be sensitively placed, there are some fundamental engineering issues which must be satisfied. The area is prone to landslides and so the natural terrain presents some challenges in terms of tower locations. The remote location is also an issue to be addressed in terms of construction. More importantly from the operational and maintenance perspective when safety and minimisation of risk are primary concerns, wind speed and wind shear also need to be considered in terms of engineering design and also passenger comfort (additional wind gauges have been installed to gather more information for the system design).
The key comments raised by various government departments and Green Groups (Conservancy Association, Green Lantau Association, Friends of the Earth, Kadoorie Farm and Worldwide Fund for Nature Hong Kong) have been taken into account for formulating the emergency rescue plan/ trail. An outline emergency evacuation and maintenance plan has been drafted and has been circulated to various parties including the Green Groups (Conservancy Association, Green Lantau Association, Friends of the Earth, Kadoorie Farm and Worldwide Fund for Nature Hong Kong). These parties have reviewed working papers and the draft EIA report and have provided comments especially in the visual and ecological impacts (temporary and permanent losses) of the material ropeway, the emergency rescue trails and the construction of the towers. The comments received have been taken into account in the development of the Project and in particular the construction methods and the emergency rescue trail. Use of existing footpaths was a key aspect to be considered as this would reduce vegetation clearance and tree felling for access (emergency as well as for maintenance and operation).
Among the key issues considered in visual impact assessments, those most relevant to the urban section of the cable car include the degree to which the development obstructs views, the ability of the surrounding environment to absorb the new built elements, the number of sensitive receivers and their proximity to the development. The following description of the cable car route and the character of the Tung Chung environs outlines the anticipated nature of the visual impacts.
All seaward views from Tung Chung are dominated by the airport, the continuous background noise and movement of aircraft and, at times, the smell of engine exhaust. The foreground views are similarly dominated by the extensive bridge, road and rail infrastructure and incessant traffic thereon. The residents of Tung Chung will view the proposed cable car route against this backdrop and in the context of views along the coast and up the mountains.
The appearance and scale of the tower structure will depend on the cable car system selected. The cable car system will have a generally similar appearance and scale to that of a high voltage powerline, i.e. relatively transparent lattice tower structures and slender cables (refer to Section 8). The main difference is the moving gondolas, which, compared with the movement of road vehicles on nearby roads, are quiet, efficient, safer, non-polluting and will operate generally between 7am and 11pm and only on rare occasions such as Buddha’s Birthday will 24 hour operation be considered. If the terminus is located more than walking distance from the MTR station the additional road traffic, e.g. shuttle buses and taxis, required to transport the thousands of cable car passengers across town will create a greater visual, noise and air impact in closer proximity to residents.
Visual impact assessment is subjective in nature and public perception of and response to the cable car system will be varied. Controversy often surrounds novel or unfamiliar developments. Contemporary examples include Hong Kong Bank Building, China Bank Building or the Peak Tram Terminus. Despite lively debate about their design merits, such developments have quickly become an integral part of Hong Kong. The cable car and terminus building at Tung Chung is the first of its kind and will be designed, constructed and operated to the highest standards. It has the potential to become more of a focal point and source of pride for Lantau and Hong Kong as a whole than an eyesore.
The route options were first assessed in Agreement No. CE1/97 Remaining Development in Tung Chung and Tai Ho Comprehensive Feasibility Study (TDD): Working Paper No. WP10 Review of Cable Car Proposal (Mott Connell Ltd, 1998) in this report, four route options were proposed and discussed. The preferred alignment was selected in the Consultancy Agreement NEX/034 Tung Chung Cable Car Feasibility Study (MTRC): Final Feasibility Study Report (1999) this report reviewed and investigated three alternative alignments for the cable car route in addition to the four alignment options examined in the TDD’s Study (refer to Figure 2.1). The following sections describe the benefits or disadvantages of each of the alignments considered.
Alignment 1
This option was rejected because of its impact on the adjacent developments. Hence, it was given no further consideration.
Alignment 2
The first portion of the Alignment from the terminal at Tung Chung Area TC74 would cause visual impact to the housing sites in Tung Chung Area TC38 and TC81 and would impinge on the housing site in Tung Chung Area TC81. Since this route is closer to those indigenous villages in the Tung Chung valley, it would have adverse visual impacts on the existing residents, particularly in areas TC60 (Ngau Au Village), TC65 (Shek Lau Po), TC62 (Mok Ka) (refer to Figure 2.2) as well as the houses scattered around Lam Che and Nim Yuen to the north of Mok Ka. The majority of the alignment would be clearly seen from North Lantau New Town and would cause visual impact to the largest group of the sensitive receivers.
This alignment crosses the second largest area of secondary woodland (1590m) with relatively high potential for tree felling to accommodate tower construction. The Tung Chung terminal is located on the urban fringe close to residential sites in Tung Chung Areas TC 38 and TC 81 as well as village communities to the south-west. The cable car leaves the urban area and traverses the wooded hillside where it would detract significantly from the landscape character of the traditional village communities and natural hillside scenery.
The first section of the route from the Tung Chung Terminal would offer a good view of Tung Chung Road, Tung Chung valley and the east end of the airport island. The spur line of the first knoll would however block the view to the west end of the airport. The portion of the alignment that can see Po Lin Monastery/ Giant Budda is relatively short and the view is relatively poor.
These alignment would traverse the countryside to the east of the Monastery where many visitors to Ngong Ping enjoy the quiet area (Tea Gardens etc.) beyond the bustle of the tourist development. No existing footpaths run close to the alignment and as such maintenance issues and operational requirements would need to be considered. Extensive vegetation (secondary woodland) cutting would be required for access and maintenance. This alignment also crosses habitats (secondary woodland) considered to be ecologically important and thus was not considered to be a favoured option.
Alignment 3
The first portion of Alignment 3 from the terminal at Tung Chung Area TC711 would cause visual impact to the housing sites in Tung Chung Areas TC46 and TC37 (refer to Figure 2.2). The majority of the alignment is clearly visible from North Lantau New Town and would cause visual impact to the largest group of the sensitive receivers.
The alignment crosses the greatest area of woodland (2090m) and has therefore the greatest potential for tree felling to accommodate the tower construction. This alignment begins in Tung Chung Area TC711 on the western fringe of Tung Chung and traverses the hillside directly west of housing sites in Tung Chung Areas TC37 and TC 46. The majority of housing in these areas is surrounded to the north, east and south by predominantly urban development. In contrast, the slopes to the west offer an attractive, natural landscape setting. Therefore, the intrusion of the cable car route on to these slopes would seriously detract from the undeveloped, rural landscape character of the western flank of the Tung Chung valley. The terminal at Ngong Ping would be to the east of the Po Lin Monastery and would likely require significant tree felling to accommodate the terminal and upgraded road and utility infrastructure.
The lower 600m of the route would provide a panoramic view of North Lantau New Town and the eastern end of the Airport Island. The section of this alignment from which one can observe the Po Lin Monastery/ Giant Budda is relatively short and the view is relatively poor. The alignment would traverse the countryside to the east of the Monastery where most visitors to Ngong Ping enjoy a walk in the quiet area beyond the bustle of the tourist development.
No existing footpaths run close to these alignments and thus operational and maintenance issues would need to be considered along with significant vegetation (secondary woodlands)clearing. This alignment would have impacts on the key habitats including secondary woodlands on the east of the Tung Chung valley.
Alignment 4
The first section of the Alignment from the terminal at Tung Chung Area TC721 would visually intrude upon the residential site of Tung Chung Area TC711. The majority of the alignment is clearly seen from North Lantau New Town and would visually impact on the largest group of the sensitive receivers.
This alignment crosses similar amount of woodland (1590m) as in Alignment 2 with similar potential for tree felling (secondary woodland) to accommodate tower construction. The hillside portion of the route is very similar to that of Alignment 3.
The lower 600m of the route would provide a panoramic view on North Lantau New Town and the east end of the airport island. The section of the alignment where one can view the Po Lin Monastery/ Giant Budda is relatively short and the view is relatively poor. These alignment would traverse across the country side on the east of the Monastery where may visitors to Ngong Ping enjoying walking in the quiet area beyond the bustle of the tourist development. No existing footpaths run close to these alignments so the same comments as made for Alignments 2 and 3 apply.
Alignment 5
The first section of the alignment from at Tung Chung Area TC3 would visually intrude on the housing and residential sites in Tung Chung Areas TC4, TC721 and TC731. The proposed Town Hall in Tung Chung Area TC3 would screen most of the residential blocks in Area TC4 from the impact of the cable car alignment. The proposed uses in Tung Chung Areas TC721 and TC732 were planned for an Other Uses (OU) site, a hotel and service apartments. The closest distance of the centre line of the cable car alignment to the service apartments is approximately 100m. The number of flats in these service apartments facing the alignments is 12 in total for one floor. The cable car would generally be at a level of 5/F of the apartments and the total number of flats below this level would be around 36 assuming that the 1st and 2nd floors are for retail and other uses. It is considered that this visual concern is not significant as this is quite a common occurrence in Hong Kong situation and the residents may not necessarily object. Indeed, in the absence of the cable cars, the residents would face the airport fuel tanks, cargo buildings and the associated buildings which may not hold as much interest. This alignment would traverse the Lin Chi Temple and is closer to the residents at Ngong Ping.
No existing footpaths running close to this alignment so the comments pertaining to Alignments 2 and 3 in connection with operation and maintenance apply. This alignment is the least damaging ecologically as it impacts mainly on grassland and scrub habitats. This Alignment is clear of the ‘Dragon’s Back’ but slightly impinges on the ‘Elephant Trunk” which is significant from the Fung Shui perspective (refer to Figure 2.4).
Alignment 6
The first section is the same as Alignment 5. For the uphill section, as the alignment is on the other side of the ridge line separating North Lantau New Town and is furthest away from the Town, its impact on this large group of sensitive receivers is least significant. However, it would visually intrude on a relatively small number of residents/hill walkers on the northwest coast of Lantau.
This route utilises the same Tung Chung and Ngong Ping terminal as Alignments 5 and 7. It is the most westerly route crossing the north end of San Tau valley and following the western ridgeline to Ngong Ping. The route traverses a similar amount of secondary woodland (1430m) to Alignment 7, skirting the majority of the woodland, which is concentrated on the lower slopes and valley floor. The route is similarly concealed from Tung Chung although portions on the ridgeline may be visible as intrusions into the natural skyline from coastal villages to the west. The panorama of the Airport and the northwest coast would be enjoyed on the downhill ride with unobstructed views of Giant Buddha and Po Lin Monastery experience when approaching Ngong Ping.
An existing footpath runs close to a part of this alignment near Ngong Ping which reduces cutting new access/maintenance trails, although this alignment would impact on the woodland and stream valley south of San Tau. The Alignment is clear of the ‘Dragon’s Back’ but significantly impinges on the ‘Elephants Trunk’ (refer to Figure 2.4).
Alignment 7
This is the preferred Alignment which has developed from the modification of the foregoing alignment options. Although the initial section of this Alignment parallels the Sea Channel in front of the Tung Chung development, it is further away from the Tung Chung development and is likely to cause the least visual impact. For the hillside section, as the alignment is on the other side of the ridgeline separating North Lantau New Town, its impact on the largest group of the sensitive receivers is greatly diminished. However, it would still cause visual intrusion to the relatively small number of residents/hill walkers on the northwest coast of Lantau.
This route utilises Location E1 as the Tung Chung Terminal and has the same Ngong Ping terminal as Alignment 6. The hillside portion is however aligned still further west on the east flank of the San Tau valley just below the ridgeline. The route crosses the second least amount of woodland (1390m) skirting the main concentration of trees on the lower slopes. The San Tau valley is less developed than Tung Chung valley and the intrusion into this natural and more remote upland landscape is potentially high. However, unlike Alignments 2, 3, 4 and 5 this is countered by the seclusion of San Tau valley and the intervening ridgeline effectively concealing and helping to mitigate the landscape impacts of the hillside portion of the route from the New Town. No towers are located within tall shrubland or secondary woodland areas.
In terms of the view corridor and visual envelopes panoramic views of the New Town and the Airport will be experienced on the downhill ride. Unobstructed views of Giant Buddha and Po Lin Monastery would be enjoyed when approaching Ngong Ping on the uphill journey. This Alignment will be clear of Lin Chi Temple and is further away from the residents at Ngong Ping which is of benefit in terms of reducing the impacts on sensitive receivers. Existing footpaths run close to this alignment over quite a long length of the alignment within the Country Park, which makes use of the available existing footpaths and reserve maintenance trails. This has benefit in terms of the operation and maintenance once the system is functioning.
This section of the report provides the latest information on the tower locations and provides the principles of the Project in respect of specifically minimising impacts on areas of ecological concern.
It is a fundamental presumption, upon which the cable car system is developed, that safety is of paramount concern. Closely allied to that assumption is the minimisation of the environmental and ecological impacts associated with implementing the Project. The minimisation of ecological, noise, visual and landscape impacts has been particularly carefully considered during the development of the cable car system and encompasses the Project in its entirety and not just as part of the EIA process.
Alignment 7 was developed through an iterative process over a period of years, taking and updating information on ecology and environmental issues in the area, addressing comments made by Government and interested bodies, such as conservation groups (e.g. Conservancy Association, Green Lantau, Friends of the Earth, Kadoorie Farm and Worldwide Fund for Nature Hong Kong etc.) and through detailed surveys and studies. The alignment and the tower locations are being fine-tuned as part of the current detailed design of the Project.
The proposed alignment and particularly the tower placement requires a balance to be drawn between the sensitivity of the environment and fundamental engineering requirements (as briefly stated above). The area is prone to landslides, steep slopes and ravines and so the natural terrain presents significant challenges in the selection of tower locations (refer to the dossier of selected photos in Annex C). The remote location is also an issue during construction but more importantly from the operational and maintenance perspective when safety and minimisation of risk are a primary concern (i.e. access for emergency evacuation and maintenance).
System Issues
In the Tung Chung Cable Car Feasibility Study: Final Ecological Impact Assessment Report (1999) the ecological impacts associated with the preferred alignment and tower locations of two separate (Funitel and 3S) cable car systems were investigated. These systems had differed requirements including the numbers of tower bases. For the Funitel system it was assumed that around 21 towers would be needed to support the cable system while the 3S System (tri-cable) required about seven. Even in terms of the physical area affected a clear indication was that the Funitel system would potentially have greater impact on the receiving environment during and following construction compared to the 3S system.
The 3S system was favoured because of the reduced number of towers and was further modified to a bicable (2S) system. The latter offered lower energy consumption, very high wind resisting strength and rope guide safety (same number of towers as the 3S) and longer spans. Figure 2.5 illustrates the final tower locations at the time of preparing this EIA. It is noted that a maximum of 8 towers are needed, 5 of which are in the Country Park.
Ecological Issues
In August 2002, under a separate commission by the Territory Development Department BMT Asia Ltd. was commissioned (Agreement No. HKI 1/2002) to undertake ecological baseline surveys, which included surveys of the tower bases as shown in Figure 2.5. The attached Figure 7.2 also shows the sensitive ecological areas (“no go” areas) including the proposed locations of the towers and angle stations and Figure 7.3 shows the habitats of the Study Area. A draft ecological baseline survey report was prepared by BMT (January 2003) and the following sections draw on the findings of that study for each of the tower locations. The ecology study also draws on information and assessments undertaken on behalf of MTRC over the last five years which has been used to modify and refine the tower locations. Detailed assessments of ecological resources are given in Section 7 with summary of the findings presented below:
· Tower 1 is located in a developed area at Tung Chung Town Centre, which is of little ecological value. Design requirements dictate that a tower must be located immediately before the Angle Station along the alignment. The location was selected due to the availability of the land and lack of alternative locations in the vicinity. The tower is located further away from the Tung Chung development (than other locations considered) resulting in a reduced visual impact.
· Angle Station at Airport Island is in a partially developed area that contains a plantation vegetation community, which is considered to be of a low to medium ecological value containing only common species.
· Towers 2A and 2B are located in a developed area on Airport Island, which is of little ecological value. Design requirements dictate that a tower must be located immediately after the angle station along the alignment.
· Tower 3 is located in low shrubland, a widespread habitat that is typically moderate to poor in plant species diversity. No rare species were recorded from field inspections. The elevated position on the hillcrest conforms to design requirements of the alignment.
· Tower 4 is located in low shrubland, a widespread habitat that is typically moderate to poor in plant species diversity. A single native Camellia sp. (rare and protected) was recorded approximately 20m from the proposed tower location, the location is shown on Figure 7.2. Mitigation measures will be proposed for this species as part of the EIA. The tower is on a steep slope (approximately 40°) and falls within a relatively sensitive location due to the steep gradient of the slope.
· Tower 5 is located in low shrubland, a widespread habitat that is typically moderate to poor in plant species diversity. Design requirements dictate that a tower must be located immediately before the Angle Station along the alignment.
· Angle Station at Nei Lak Shan, which is positioned on a ridgeline, is located in grassland with scattered low shrubland.This is a very widespread habitat within the study area and in the SAR,and is typically moderate to poor in plant species diversity. A common but protected orchid species (Bamboo Orchid) was identified within 25 m from the centre of the Angle Station. As noted above proposed mitigation measures will be detailed in the EIA.
· Tower 6, which is positioned on a ridgeline, is located in Grassland with a few scattered low shrubs. Design requirements dictate that a tower must be located immediately after the Angle Station along the alignment.
· Tower 7 is located on a steep gradient in low shrubland, a widespread habitat that is typically moderate to poor in plant species diversity. This tower location was selected due to the vegetation community present and engineering requirements.
In summary:
· The tower and angle station locations have been selected in areas of low ecological sensitivity (grassland and low shrubland), which is matched with technical/ engineering requirements.
· The total area anticipated to be disturbed by the towers and the angle station locations is approximately 2 hectares.
For tower foundations on hillsides, mini-piles would be preferred where the slope is steep and large excavations are not possible. This option is also favoured from an environmental standpoint. In this case, the tower would require a concrete pad with the base to suit the slope profile or a number of smaller pads for connection to the pile heads. Raking piles would be needed against sliding. It should be noted that mini-piles should be socketed into rock (approximately 4 to 6m), and their tensile capacity, important for over-turning stability of the towers, will be as effective as their compressive capacity subject to rock joint spacing and orientation. Where the slope is not steep and excavation is permissible, or where rockhead is near the surface, raft foundations may be a more economical option to provide the base for the tower against sliding and over-turning. In determining the height of a tower on the hillside, the foundation could be a governing factor because of the restriction on excavation and the maximum number of mini-piles that could be installed.
Tower Structural Forms
Structural form must be principally determined from a safety and engineering perspective, all the while taking account of the visual impacts. If tubular steel form was used the weight would be such that only short sections could be delivered to site (by helicopter) at any given time. The lattice form is preferred from a constructability and engineering perspective and as these towers are similar to the existing style of electricity towers the impacts can be considered to be reduced as it is “more of the same” (albeit a very small number of additional towers). More details are given in Section 8 on the Landscape and Visual Impact Assessment.
Tower heights could range from 5 to 60m depending on spacing and location and the cable system to be adopted. In choosing structural forms, the following factors need to be considered:
· Primary loadings of a tower are its self-weight and wind loads it attracts, therefore the tower should preferably be light, attract minimum wind loads but at the same time be stiff enough and aerodynamically efficient against excessive movements and vibrations induced by wind.
· Constructability is a major issue as imposed by site constraints. For towers on rugged hills with construction access only possible by air, the towers would need to be assembled on-site in segments light enough to be transported by helicopters.
· Maintainability should also taken into account in selection of the structural forms which should be such to avoid corrosion, if possible, and to facilitate maintenance.
· Aesthetics - pleasing appearance and integration with the environment are important considerations.
· Uniformity of design is equally important as it will facilitate construction and reduce cost and time.
These factors have been used to evaluate three basic options of construction materials for the towers viz., cast-in-place reinforced concrete, precast concrete and structural steel. A preliminary analysis suggests that structural steel is the best option as described below.
A reinforced concrete tower in the form of a circular, rectangular or octagonal hollow section can be constructed by cast-in-place concrete using slipform. The main advantage of cast-in-place concrete is its common use for construction in Hong Kong. For towers on rugged hills, delivery of wet concrete by helicopters would be a more costly option than delivery of prefabricated steel members, as a concrete tower is significantly heavier than an equivalent steel tower and therefore would require a greater number of helicopter flights to each site. In hillside environments, finishes to concrete surfaces would have to be applied on-site; the work would be time consuming, expensive and its quality difficult to control.
Precast concrete construction making use of precision moulds, steam curing and early finishing under factory controlled conditions will resolve some of the above problems, and is therefore be preferable to cast-in-place construction. However, its heavier design is still a disadvantage when compared to steel construction.
Structural steel is suggested to be the best construction material for the towers because of the imposed site constraints. With this in mind the following points are important considerations:
· As much prefabrication as possible should be undertaken, taking advantage of mechanised welding, application of corrosion protection and early painting under factory controlled conditions. It should be noted that each prefabricated section should be designed for ease of handling by helicopters (application of lifting eyes and alignment markers) and its weight be compatible with the capacity of the helicopter used.
· Fabrication details should be kept as simple as possible and should be designed to avoid corrosion and facilitate maintenance. Most likely, the sections would be joined together by high resistance bolts which are tightened to torque with adequate fatigue resistance.
· Tolerances for on-site connections should be made generous because of the difficulties associated with working on steep slopes.
· To achieve uniformity of design, a flat concrete base would be required for each tower and most likely cast-in-place, a method of construction easily suiting the various site conditions. For the situation of a tower on a slope, if mini-piles are used, a pile cap with the bottom to suit the slope profile and a flat top or a number of pile caps with the same top level would need to be constructed in-situ. If footing foundations are possible, the tower would be directly anchored into the top of the footing.
It is envisaged that because of the high wind loads that the towers would be required to be designed for (as per the Hong Kong Wind Code), a latticed (truss) tower attracting minimum wind loads, yet inherently rigid, is preferable to a slim closed type composed of welded thin plates forming a hollow section in the shape of a box, a circle or an octagon, attracting full wind load. A slim hollow tube tower appears to be more architecturally pleasing. A compromise could be that for towers taller than a certain height, the bottom section could be latticed providing a rigid skeleton with the upper section a hollow tube.
For the purposes of the EIA, it has been assumed in the worst case, that a 40m (maximum) tall latticed tower would have four footings of approximately 5m x 5m. The land requirements plan indicates an area of 30m x 30m would be required at each tower. This does not imply that all this area would used for the tower base, rather that the four individual footings (maximum 5m x 5m each) would be located within the 30m x 30m area. Prefabricated steel assemblies can be easily lifted by helicopters and on-site connections will be straight forward. For a hollow section of these dimensions and a steel thickness of about 6mm (adjusted to account for stiffeners), the maximum length that can be lifted by a helicopter is about 2.6m (if the maximum carrying capacity is 875 kg), thus requiring about 8 or less flying trips (upper sections could be smaller or thinner, enabling longer sections to be air lifted) to build a fully completed tower (not including the top cross-arms).
As discussed, for towers to be built on steep hillsides, the size and height of the towers could be limited by the foundation capacity achieved at particular site locations. Alternatively, the sites of towers could be selected to minimise construction difficulties to achieve the desired foundation capacities as required.
The general method of rescue is still by vertical rescue and with the rescue cabins installed within sections that are inaccessible at ground level. None of the installations have experience of breaking down or accidents that require emergency evacuation of the line. They have not maintained a special rescue team for this purpose. The general principle adopted is to make the line running again in all cases wherever possible and bring the passengers back to the stations in their own cabins. In case of any breakdown, a service cabin which is operated independently of the passenger ropeway will be sent out to repair the system and vertical rescue is used only as the last resort when all other ways fail.
Most of the systems in Switzerland and Austria cross highways, rivers and powerlines. No special measures are installed to prevent accidents caused by falling cables or cabins. The manufacturers consider that the cables for the systems are safe elements and will not consider in normal design the case that the cable breaks. No specific clearance is required along the cable car alignment by the Swiss or Austrian authorities provided that the alignment is at a sufficient horizontal and vertical clearance from and above the trees. Trees are removed only when the cable car route is close to or interfere with the trees along the alignment.
Provision of an emergency rescue trail is required as part of the overall rescue system. As required by the Electrical and Mechanical Services Department, the emergency rescue trail of not more than 1.5m wide will be located beneath the cableway (It should be stressed that 1.5m is the width of the trail at Ocean Park and the width of the trail has yet to be agreed with Fire Services Department. If a wider trail is needed then a variation of permit will be sought). It will be formed generally using natural materials (with meanders and possible boardwalks weaving through the Country Park and its future extensions) to provide a proper and safe route for transportation of passengers in emergency situations and it will be open for public use. It must be stressed that the primary concern is to provide a safe route for emergency access from the cable cars and the passengers using the system will not necessarily be equipped for hiking or strenuous exercise. In this case the physical harshness of the environment must be taken into account in steep (and hazardous) terrain when providing the emergency rescue trail.
The trail will also serve as the maintenance access (and utilities channel for buried fibre optic and electrical cables to provide power to the towers and possibly security systems) for the cable car system and will be part of the hiking trail network within the Country Park. In addition, the trail may also contain power and communication cables which are needed to maintain safe operations. All of these requirements must be accounted for in the final implementation of the proposed rescue trail.
The proposed emergency rescue trail will be no more than 1.5 meters wide to allow for the appropriate safe width for the rescue procedures. Although, the proposed emergency rescue trail will traverse a significant length of the cableway, it is particularly necessary at locations not more than 60m in height, these are:
· between Tower 3 and Tower 6 including sections with steps (in areas where the gradient is greater than 1 in 4). For these short sections of the rescue route the steps will be constructed using ready formed blocks (e.g. wooden, recycled plastic or expanded metal walkways.) to provide safe passage in the short steep sections; and
· between Tower 7 and Ngong Ping Terminal.
The existing country park trail will also be upgraded (with steps in gradient greater than 1 in 4 again using ready formed blocks to provide safe passage in those steep areas) from Tower 3 towards Tung Chung. It must be stressed that while the principle of only using natural materials in the formation of the rescue trail is the design presumption, passengers in the cabins will not necessarily be equipped for hiking and so safety is fundamental.
The emergency rescue trail primarily intersects grassland, low shrubland and a small section of tall shrubland/ woodland between Tower 3 and Tower 4 (and small sections between Tower 6 and 7). The total area required to be cleared will be less than 1 hectare with the majority of vegetation representative of the study area, being grassland and low shrubland. The sensitive vegetation (woodland and tall shrub) within the study area is shown in Figure 7.3 and the different vegetation communities are described in Section 7.
A total of six touch down points for helicopter access (i.e. to rescue passengers who cannot walk to safety) have been preliminarily selected on grassland (with a few scattered low shrubs) at strategic locations on ridgelines that provide a suitable landing surface. It should be stressed that no concrete will be used for these touch down. Three locations agreed for use by Government Flying Services connected to the proposed rescue trail, one by Tower 3, one by Tower 4 and one by the Nei Lak Shan angle station (Refer to Figures 2.17-2.19). Ecological impacts on these sites have been identified, through site visits, to be insignificant (based on worst case scenario).
Well proven cable car systems have been developed over the last few decades in response to various climatic and geographical conditions as well as physical constraints. Factors which influence the choice of the cable car system are summarised below. For each of the systems examined, the following process has been used to systematically consider and appraise the system requirements.
The tower locations and the longitudinal profiles for the above systems are shown in Figures 2.6 to 2.11. It should be noted that the number, locations and heights of the towers shown in these figures are only indicative of the scale of requirements for the respective systems.
The basic Funitel system would not be able to span across the Sea Channel and would require a tower to be constructed within the Sea Channel. This is a major disadvantage of the system on top of its high energy consumption and maintenance costs.
Both the 3S and Bi-cable systems have similar requirements in terms of numbers and height of towers. Both systems can span the sea channel without requiring any footing towers in the marine environment.
The type of preferred cable car system based on the previous selection criteria was changed to the bicable circulating ropeway system (manufactured by Leitner). The preferred cable car system was selected because of the following reasons:
- Lowest energy consumption of all circulating system ropeways:
· low rolling resistance of the vehicles, plastic on locked track rope;
· small hauling rope diameter due to hauling function only; and
· less rope carrying sheaves on the towers.
- Very high wind resisting strength and rope guide safety
- Unlimited operation is possible up to a wind velocity of 80 km/h in cross direction to the axis of the ropeway;
- The hauling rope stabilies the vehicle particularly in the critical area during the passage of towers
· the haul rope is guided in rope sheaves with high rims; and
· the track rope is guided in rope saddles with an angle of wrap of approx 180.
- Rope position monitoring on the towers by earth detector
· the isolated haul rope automatically triggers the earth detector in case of contact with the earthing brackets.
- Less towers, large spans
- Due to the separate carrying and hauling functions of the ropes the same longitudindal section as for to-and-fro type systems can be obtained; spans of far more than 1000m are no problem.
- High transport capacity
· capacity;
· travelling speed; and
· transport capacity.
- Station size
· the station sizes directly depends on the chosen travelling speed. The bicable circulating system does not require more space than any other circulating ropeway system.
The Government Flying Services (GFS) originally stated that the towers and cables strung over the Tung Chung Channel between the Airport Island and Tung Chung should not be higher than 60m above ground level although this requirement was relaxed (in principle) during bidding stage. This needs to be discussed further.
Initial discussions with Highways Department indicated their requirements to include:
· The minimum clearance between cable car bottom and road surface is to be 6 to 7m.
· To ensure that no passengers can throw dangerous particles from the cable cars down to the road, ventilation openings and windows inside the cabins will be restricted by mechanical means.
· The cable car operator shall carry out regular maintenance to ensure no loose parts from the system will drop down onto the road.
One of the main requirements for the cable car system is its resistance to wind. To ensure that the cable car system is operational throughout the year, the preferred system must not only be able to withstand the average and gust winds but also must remain operational during such conditions.
In Ocean Park where the Monocable system issued, the operating procedure is whenever the wind sensors installed at the top of the two highest towers record three no. times of wind gusts of more than 76 km/hr, the systems will need to be shut down. Based on the information from Ocean Park, there were approximately 30 days in 1998 that the system was shut down due to strong wind.
Only limited wind data are available in Tung Chung and Ngong Ping and to address this issue four wind gauges have been installed, one each near tower locations 3, 4, 7 and 6 – Angle Station. Figure 2.12 shows the wind gust data recorded at the wind station at Tung Chung Police Station for a period of 16 months between 1994 and 1995. These data show a relatively calm wind situation at the low level of the proposed cable car alignment. Figure 2.13 shows the wind gust data recorded at Nei Lak Shan (at approximately 740mPD) for a period of 21 months between 1994 and 1998. These data show that for quite a proportion of time the 76km/hr wind gust speed were exceeded. In statistical terms, it is estimated that approximately 17 days within a year this will occur. As a reference, for a Tropical Cyclone Warning Signal 3, it means that strong wind is expected to blowing in the Victoria Harbour, with a sustained speed of 41-62 km/h, and gusts, which may exceed 110km/h. Operation of cable car under Signal No. 3 is however prohibited under the Aerial Ropeways (Operation and Maintenance) Regulations.
To maintain the operation of the cable car between Tung Chung and Ngong Ping all year round, it is recommended that the cable car system to be adopted should be able to resist a wind speed of 90 km/hr. Funitel, bi-cable and 3S all achieve criterion.
To determine the restrictions of operation vis-a-vis wind speed it is important to know the safety margins that have been allowed in the stated permissible wind speeds (i.e. at what persistent wind speeds the systems will start to fail by grip detachment or cables coming off the sheaves for example). However, there are no cable car manufacturers that can provide this information. In view of the disastrous consequence that will be resulted from this type of failure, it will be prudent to adopt a conservative approach by using these permissible wind speeds as the criteria for terminating the operation of the systems even for a temporary period. This is believed to be the criteria adopted in Ocean Park for their cable car system.
Wind of a particular speed do not normally last long. The quoted persistent wind can be interpreted as the mean wind speed which is the average of the wind speeds over a sufficiently long period of time. However, relying on such a data for the monitoring of the cable car operation would be too risky as the wind phenomenon is such a random event that an intolerable wind gust may occur within the monitoring period. The monitoring procedure should make use of a data that can be recorded ‘instantaneously’ as the determining data. For wind, it refers to the gust speed.
Gust speed (of certain gust duration t) is usually defined as the largest averaged wind speed with an averaging period of t seconds occurring within a certain period. Thus it can be visualized that, the shorter the gust duration the higher will be the gust speed. On the other hand, if the gust duration is lengthened, then the gust speed will be lowered, and eventually will approach the hourly mean wind speed. The gust speed is often expressed in terms of the gust factor which is defined as
G(t) = v(t)
V
Where G(t) is the gust factor of gust duration t;
v(t) is the gust speed of gust duration t; and
V is the hourly mean wind speed.
In general they have the shape of an exponential decay curve with values approaching unity at large gust durations. Furthermore for the same gust duration, gust factors at different locations have different values. In fact they are different at different heights even at the same location.
It has been accepted in some similar past projects that a gust factor of 1.5 to 1.6 is appropriate. Applying a gust factor of 1.5 to the stated persistent winds that the respective systems can tolerate under normal operation, the following are the gusts that should be used as the criteria for terminating the operations of the respective systems.
· Monocable - 75km/hr
· Bi-cable - 135km/hr
· Funitel - 135km/hr
· 3S - 135km/hr
Construction of the land towers between the Tung Chung Terminus and the angle station will require both temporary traffic management and relevant permissions from the Highways Department and the Airport Authority (AA), in terms of both access of the existing road network and allocation of work areas.
Terminal Buildings
Construction methods for the terminal buildings will follow standard practices and will include excavation, foundations, superstructure, cladding and finishing.
Angle Stations
At the angle station the housing is expected to be of light steel structure (due to constraints on the import of materials to the Country Park (for the Nei Lak Shan angle station) and the need to blend in as far as possible with the surroundings. At the Angle station at the airport island there will also be a maintenance building (two to three storeys high) which will be designed to blend into the surroundings.
Towers
The towers will essentially be constructed using prefabricated sections for the tower itself which will be founded on raft/bored pile to rockhead type foundations or small pad foundations. As all materials will need to be imported to site either by hand carry or by helicopter (or material ropeway) the use of as much off-site prefabrication as possible is assumed. This has added environmental benefits of minimising wastes generation and offsite disposal, reducing potential for spillages or dispersal of materials on site.
Emergency Rescue Trail
The emergency rescue trail could be provided by use of small handheld tools to clear the vegetation and to provide a narrow shallow trench for the laying of systems (fibre optic) cables. The trench will immediately be backfilled and reinstated to the visual impacts will be reduced significantly. The design of the trail will generally follow the principles developed by the New South Wales National Park Service (1985) Walking Track Construction Guidelines: A guide to the construction and maintenance of walking trails and those adopted in Hong Kong Country Parks as illustrated on Figure 2.14. Illustrations of typical features of the rescue trail are demonstrated on Figure 2.15.
Use of Helicopters
Due to the fact that the majority of the ‘Preferred Alignment’ i.e. Alignment 7 is located within a mountainous area, a large portion of which being within the North Lantau Country Park, with no direct sealed or metalled road access (or even rough tracks) to many sections of the alignment, construction of the towers and angle station is deemed to be only feasible by means of helicopters. Additionally, potential access constraints on the construction traffic use of the Ngong Ping Road may also require materials, and ultimately construction of the Ngong Ping Terminal development, to be in part by the use of helicopters.
Wide experience has been gained over a number of years both within Europe, North America and Asia (most recently with the building of the Genting Highlands Project in Malaysia) with the construction of cable car systems using helicopters. Within Hong Kong although helicopters were not believed to be used on the construction of the Ocean Park system, similar methods of construction in similar environmental conditions, have been utilised for the construction of electrical towers for China Light & Power.
In Hong Kong two helicopter companies currently exist which undertake building projects (Heliservices and Helicopter Hong Kong). Heliservices have been established for many years and have a wide experience in many different construction projects with an impressive safety record (Helicopter Hong Kong have only been operating within the SAR for approximately two years).
Mott Connell has carried out discussions with both helicopter companies and carried out helicopter surveys of many of the alignments under consideration including the preferred alignment. From these activities the following major points of the potential use of helicopters have arisen:
· Flying restrictions exist over Chep Lap Kok airport (cannot be overflown), Tung Chung Town Centre (flights are required to be at least 500 feet above ground level) and low level flying is not permitted over the summit of Nei Lak Shan where a communications tower is situated.
· Logging of flight plans and flight control is dealt with by the air traffic controllers at Chek Lap Kok airport.
· Aerospatiale Lama Helicopters have been successfully used for the construction of the electrical towers with a standard lifting hook capacity of 875kg. They have been used to carry both steel lattice segmental sections and concrete (transported in specially designed non-leakable 0.3m3 bins/hoppers). All steel sections have lifting hooks and alignment markers. If the loads required to be transported are greater than the 875kg then other types of helicopters with increased lifting capacities could be made available.
· The standard area required for a touch down points is usually twice the diameter of the rotor disc of the helicopter used. If Lama type helicopters were to be used then this would equate to an area in the order of 33 x 33m (this is a conservative approach with the area equivalent to twice the length of the helicopter with rotors turning, a potential requirement of the Hong Kong Authorities).
· Under the current regulations no helicopters lifting materials under hook will be allowed to fly over public roads or bridges.
· Lama type helicopters carry sufficient fuel (Jet A1 Aviation) for approximately one hour of flight. No refuelling will be carried out at the touch down points in the Country Park.
· The touch down point should be sited in an area to allow safe and easy landing and takeoff, i.e. flat locations away from buildings/structures and trees.
It is obvious that if construction by use of helicopters is to be undertaken, then the positioning of the touch down points should follow the above requirements, as well as, to minimise the flying time between the work site and the cable car alignment. It should also be noted that all tower locations have been overflown and the potential for dropping passengers/materials checked. There are a number of suitable locations which would not require any work to be done to make them usable. It would be a good practice if the location of any specific touch down point was in the vicinity of the Construction Contractor’s work site, which would be used for prefabrication of structural forms and production of wet concrete, as well as a staging post for helicopter transportation (such as at the possible Airport Worksite).
A suggested location for the touch down point is approximately 2.60km from the Angle Station and 3.65km from the Ngong Ping Terminal development, equating to approximately 4 round trips per helicopter per hour.
An additional touch down point would be preferable, with perhaps the only feasible alternative being a large concrete open area within the proposed Ngong Ping Terminal development. However, the Po Lin Monastery and government agencies may impose flying constraints and at this stage it is thought that limited use of this site may only be allowed. This site could also act as a secondary Contractor’s work site for both storage and fabrication facilities and potentially limited road transportation of materials could be allowed during restricted hours.
The number and type of helicopters selected for construction works will depend on the cable car system chosen (i.e., the number of towers), structural forms, i.e., steel or concrete, weight lifting capacities required (which may include the use of larger Russian built machines with greater lifting capacity than the Lama type) and weather conditions experienced and the successful contractors proposal. It should be borne in mind that both at the proposed tower locations and the site of the proposed angle station, topographic, ground stability and environmental controls may result in a very small working area at each of these locations. Therefore the handling of large steel structural units and greater volumes of 0.3m3 of concrete, delivered regularly potentially over very short time intervals, may not be feasible.
Transportation to the angle station will also involve the lifting of motors, gearboxes and drive wheels irrespective of the cable car system adopted. This would require these units to be broken down into smaller components and reassembled on site (which may prove difficult and be unacceptable), or alternatively a larger lifting capacity helicopter used for this operation.
In conclusion, helicopter construction is feasible for those sections of the cable car system which are not accessible by roads. In further chapters of the EIA the impacts associated with delivery of material by helicopter will be assessed.
Temporary Material Ropeway
An alternative means of conveying materials to and from site is to use a material ropeway. The system would need to convey loads of around 8 tons and a suggestion has been made by the systems suppliers that such a system would be feasible if constructed in parallel to the preferred Alignment. The distance between the two systems would be of the order of 20m. In this situation the temporary material ropeway would need to be provided in two sections as shown on Figure 7.3 and would be supported by a series of “towers” (at least 19 towers would be required) which would be used to convey the track rope. The “towers” would be anchored in a temporary manner in one of the following three ways:
(i) Anchor into natural soil
A wooden pillar with an average length of 1.5m is dug in the soil and the ropes are wrapped around it. This procedure is based on experience gained in Europe over decades.
(ii) Anchoring into rock
The guide ropes would be anchored directly into rock by means of anchor bolts.
(iii) Anchoring into small foundations
The ropes are anchored into temporary concrete foundations.
Of the three options the latter has been specifically rejected as it would involve more construction work within the Country Park, the concrete bases would need to be prepared and then removed, a concept which is contradictory to the overall ethos of this Project.
Around 19 temporary towers would be required, and helicopters would be needed for delivery to the temporary tower locations. Assessments have been carried only for both systems and focus particularly on the ecological impacts (specifically disturbance) associated with the provision of a second (albeit temporary) ropeway. The details of the assessments are included in the following sections (specifically noise, ecology, visual and landscape), which conclude that although the use of a material ropeway is technically feasibly, it is not of benefit to the sensitive environment of the Country Park.
As part of the overall development of the Project a ‘Theme Village’ will be created at Ngong Ping (current zoning is “Other Specified Uses” and “Tourist Corridor”) on the draft Ngong Ping OZP No. S/I-NP/1. This will be subject to a Section 16 Planning Application and to date details are not known. The concept will be low physical level of development in keeping with the tranquil environs. The style could be similar to that illustrated in Figure 2.16.
[1] Reclamation of Pak Sha Tsui Island and the proposed development in areas TC71, TC72 and TC73, has been dropped completely.
1 Reclamation of Pak Sha Tsui Island and the proposed development in areas TC71, TC72 and TC73, has been dropped completely.
1 Reclamation of Pak Sha Tsui Island and the proposed development in areas TC71, TC72 and TC73, has been dropped completely.
1 Reclamation of Pak Sha Tsui Island and the proposed development in areas TC71, TC72 and TC73, has been dropped completely.